I would like to analyze spray distribution inside a combustion chamber. I am assuming the combustion chamber to be represented by a simple cylinder.

When I create a cylinder in GAMBIT and apply volume mesh to it, I notice that the flat faces have been meshed using Pave. From some other thread on this website, I found out that perhaps the best way to obtain regular rectangle (quad) shape elements is to follow a down-top approach.

I have the following questions:

1) How can I ensure that the cells on the flat faces are square (or rectangle) and not pave type? (Please explain the down top approach if possible)

2) The atomizer is located at the center. Therefore, I would like to have a fine mesh near the center of the cylinder (flat circular face). How can I achieve this?

I have a fair idea of what I want to achieve but I am not able to mesh it correctly. Basically, I am describing the combustion chamber which you may have seen in a number of papers in which the mesh is very regular, and fine near the center but coarse towards the wall of the cylinder.